Roller Rockers in Stock

[Alan Roehrich]

Kris,
I'm going to try to address as many of your questions in this post as possible, given the constraints of a bulletin board, and the need to not tell everyone everything.

Rocker arm weight is not critical, stock rockers are not heavy, rocker weight in Stock has little to do with valvesprings. It is not the weight of roller rocker arms that will allow higher RPM, an aftermarket roller rocker arm will most often be considerably heavier than the stock part, especially if the stock part is stamped steel, regardless of whether the aftermarket rocker arm is stainless steel or aluminum. For valvesprings and RPM range, rocker arm weight is only important from the center of the stud or shaft toward the valve, what the other half weighs is practically irrelevant.

Again, we have a racer, he can turn X000 RPM, to go higher, he needs more valvespring, and he'll break rocker arms anyway, even without more valvespring. Turning another 1000 RPM will allow him to go faster. Give him roller rocker arms. Now, he can go turn 1000 more RPM, and find out what breaks next. In order to make HP 1000 RPM higher, he needs a new camshaft with more duration or more lobe separation angle or both, since he is lift limited. So, now he's bought new rocker arms, new pushrods to go with them, to keep his lift correct, new valvesprings to turn more RPM, and a new cam to make HP at a higher RPM.

Again, go search and find the principles behind the Crane "quick lift" rockers they sold a few years back. I'll give you a quick hint. The idea behind those rocker arms was you could change the ratio of the rocker arm at low lift, where the valve opens and closes, without changing the ratio at maximum lift (where NHRA measures lift and determines rocker ratio in Stock, by the way) so that you could make significant changes to your camshaft profile at the valve, without altering maximum lift, so you did not have to worry about changing valvesprings, or possibly having to cut the top of the valve guides, etc.

All I'm going to say about valves and valve jobs is that when you change the amount of time, percentage wise, that you spend at certain amounts of valve lift, then you need to change the valve job, and maybe the valve, to take advantage of that change. Remember, we no longer have a real valve job rule in Stock Eliminator, you can run any angle you want, as many angles as you want, the only limit is how far the valve job goes into the bowl of the port and the chamber of the head.

People keep talking about the cost savings this will bring. They ignore the other parts that will get changed. Those parts cost money, too. They ignore the increase in RPM, that will cost money, too. This is not going to make Stock Eliminator one dollar cheaper. This is in fact going to allow people with a lot of money to spend more money with more expensive engine builders who can do more testing to better take advantage of the new rule. This will not bring the "have nots" closer to the "haves", it will only serve to further widen that gap.

So far, we have only addressed the costs inside the engine, with regards to the ability to turn more RPM. That ignores headers and collectors. That ignores torque converters. It ignores transmission ratios. It ignores rear end ratios.

A Stock Eliminator engine is all about the combination and the complete package. A Stock Eliminator car is exactly the same. When you change a rule on one critical part, that rule and that part have effects on the entire car. In Stock Eliminator, it is NEVER about just one part.